The purpose of this paper is to report the reproductive experience in 31 infertile patients with mild endometriosis who were not treated by surgery or medication. A series of 31 cases of laparoscopically diagnosed mild endometriosis were followed up without therapy for a period of 36 months. Ten patients received artificial insemination by donor (AID) because of male-related infertility; 21 patients had well-timed postcoital tests and monitored ovulation cycles. Life-table analysis of conceptions was used for presentation of the pregnancy rate. The group of patients whose husbands were azoospermic had a 90% pregnancy rate within 18 months, with a mean of 3.5 treatment cycles for pregnancy. The nonazoospermic couples had a 47.6% pregnancy rate within 18 months, with a mean of 7.2 monitored cycles for pregnancy. The calculated median delays for the series of patients who conceived were 1.9 cycles. The whole series (n = 31) of patients with mild endometriosis had an 8.3% monthly pregnancy rate within 18 months and a 61.2% cumulative pregnancy rate within 18 months. We have come to the conclusion that mild endometriosis does not interfere with female fertility, and patients with this extent of disease should not be treated for a trial period of at least 18 months as an alternative to more aggressive therapy.